Fabrics with improved web transfer characteristics

ABSTRACT

A PROCESS FOR IMPROVING THE PARTING OR TRNASFER CHARACTERISTICS OF MONOFILAMENT POLYMERIC FABRICS IN SUPPORTING AND TRANSFERRING MOIST WEBS FROM ONE STEP TO ANOTHER IN PAPERMAKING AND NON-WOVEN WEB MANUFACTURING OPERATIONS. IMPROVED TRANSFER CHARACTERISTICS IN THE MONOFILAMENT POLYMERIC FABRICS ARE ACHIEVED BY ABRADING AWAY THE KNUCKLE SURFACES THEREOF WITH A FINE ABRASIVE MEDIUM TO INCREASE THE KNUCKLE IMPRINT AREA OF THE FABRIC. THE IMPROVED PARTING CHARACTERISTICS ENGENDERED IN THE MONOFILAMENT POLYMERIC FABRIC BY THE ABRASIVE TREATMENT IMPROVE WEB TRANSFER, WEB DRYING, WEB PRODUCT CHARACTERISTICS AND GENERAL MACHINE OPERATION.

Mm 30,1971 ,4, R DBER'G m1. 3,573,164

FABRICS WITH IMPROVED WEB TRANSFER CHARACTERISTICS Filed Aug. 22, 1967 2Sheets-Sheet 1 lNvliNloRs 7 Norman D. Frfiedberg BY Charles L. Wosubu,II

ATTORNEY March 30, 1971 FR B ET AL 3,573,164

FABRICS WITH IMPROVED WEB TRANSFER CHARACTERISTICS Filed Aug. 22, 1967 2Sheets-Sheet 2 UNTREATED FABRIC TREATED PEEL FORCE ,GRAMS PER INCH OFWIDTH FABRIC I I I I I 30 4O 5O 6O 7O 8O 9O FEELING CONS|STENCY,PERCENTFIBRE WEIGHT INVENTORS Norman D. Friedberg Fig 9 Charles L. Wosobu,1[

BY WM? @124 ATTORNEY United States Patent O 3,573,164 FABRICS WITHIMPROVED WEB TRANSFER CHARACTERISTICS Norman D, Friedberg and Charles L.Wosaba H, Cincinnati, Ohio, assignors to The Procter & Gamble Company,Cincinnati, Ohio Filed Aug. 22, 1967, Ser. No. 662,367 Int. Cl. D21f1/10 US. Cl. 162--348 8 Claims ABSTRACT OF THE DISCLOSURE A process forimproving the parting or transfer characteristics of monofilamentpolymeric fabrics in supporting and transferring moist webs from onestep to another in papermaking and non-woven web manufacturingoperations. Improved transfer characteristics in the monofilamentpolymeric fabrics are achieved by abrading away the knuckle surfacesthereof with a fine abrasive medium to increase the knuckle imprint areaof the fabric. The improved parting characteristics engendered in themonofilament polymeric fabric by the abrasive treatment improve webtransfer, web drying, web product characteristics and general machineoperation.

BACKGROUND OF THE INVENTION This invention relates to improvements inpapermaking and nonwoven web manufacturing operations and to theprovision of formation and carrier fabrics which contribute to theefiiciency of such operations. More particularly, the invention providesan improved monofilament polymeric fabric for use in papermaking andnon-woven web manufacturing operations wherein the surfacecharacteristics of such fabrics are of operational and productcharacteristic importance.

Specifically, the invention in one important embodiment consists of animproved monofilament polymeric fabric of the type used for transportinga moist web through the press and drying sections of a papermakingmachine, which monofilament polymeric fabric has been improved byabrading its surface with a fine abrasive medium to increase its knuckleimprint area.

In referring to monofilament polymeric fabrics herein, applicants intendreference to moist web carrier fabics woven, for example, from thepolyamide fibers, vinyl fibers, acrylic fibers and polyester fibers soldunder the respective trademarks of nylon, Saran, Orlon and Dacron. Whileboth warp and woof filaments in fabrics can be made up of a multiplicityof fibers, the present invention is concerned with warp and wooffilaments comprised of one fiber, i.e., monofilaments. The warp and woofmonofilaments have a diameter of about 0.008 inch to about 0.20 inch,and the carrier fabrics can be of any specific construction; forexample, plain weave, single or double crimped, twilled and semi-twilledfabrics can be utilized. The term knuckle imprint area refers to thearea imprinted on an adjacent plane surface by the knuckle cross-overpoints of the warp and woof filaments of a monofilament fabric. It isnoted that the warp filaments of the fabric run parallel to the machinedirection of papermaking and non-woven web manufacturing machines toform a continuous carrier belt; woof filaments run in the cross-machinedirection.

In the formation, pressing and drying of a moist web in Fourdrinier orother papermaking operations as well as in the manufacture of non-wovenwebs, persons skilled in the art will recognize that several transfersof a partially formed or bonded and/or partially dried web with littlemechanical strength occur. These transfers, assuming the initialformation of a desirable Web structure, are

3,573,164 Patented Mar. 30, 1971 of importance in that they can onlydisrupt bonds, entanglements and other mechanical and chemical featureswhich contribute to the desirable structure of the web. To avoid theforegoing transfer problems and to satisfy other criteria, an idealmonofilament polymeric fabric for web manufacturing, and particularlypapermaking operations, should possess characteristics which allow saidfabric to adhere sufficiently to a web structure at its various stagesof formation, pressing and drying to act as a carrier. At the same time,the monofilament polymeric fabric should not interfere with the webstructure or impart undesirable characteristics to its structure duringtransfer.

Papermakers, for example, have long known that paper webs in theirinitial stages of formation, pressing and drying will naturally transferfrom a rough to a smooth surface, i.e., papermakers have depended on thenatural tendency of an initially formed paper web to transfer from aFourdrinier wire to the felt conventionally used in the press section ofa papermaking machine. Modern papermaking practice has, however, inseveral instances departed from the normal sequence. of Fourdrinier ofsimilar formation wire to pressing and drying felts. In theseoperations, for example in the operation of a paper machine according tothe teaching of US. 3,301,746, improved transferability is desired, andthe monofilament polymeric fabrics used should not contribute factors tothe final paper product other than those desired by the papermaker anddesigned into the paper product.

In particular, it has been learned through experience that the use ofmonofilament polymeric fabrics in the press and drying sections of apaper machine introduces problems in the transfer of a moist paper webto a drying surface. Although it might be expected that continued usewould polish the knuckle surfaces of such a monofilament polymericfabric to make release of a moist paper web easier in late fabric life,such did not prove to be the case. Wear-induced fibrils on the knucklesurfaces of such used fabrics interfered with the release and transferof moist paper webs and reduced the tensile strength of the resultingpaper products.

SUMMARY OF THE INVENTION Inasmuch as a means of reducing or preventingfiber bond rupture was desired as a means of increasing product tensilestrength as were other improvements in papermaking and non-woven webmanufacturing operations, the monofilament polymeric fabric and processfor its preparation which comprise this invention were developed. Ingeneral, the present monofilament polymeric fabric is prepared byabrading the knuckle surfaces of a monofilament polymeric fabric toincrease knuckle imprint area and polish knuckle surfaces. Thepreparation or pre-treatment is continued with a fine abrasive mediumuntil the knuckle imprint area of said fabric is about 20% to about 50%of the fabric surface area. The knuckle imprint area of a monofilamentpolymeric fabric before pre-treatment is about 6%to about 15% of thefabric surface area.

Contrary to normal expectation, continued use on a paper machine doesnot polish the knuckle surfaces of a monofilament polymeric fabric notaccorded the abrasion treatment of the present invention; but ratherwears these knuckle surfaces in such a way that a fine fuzz or fibriltuft is developed at various points thereon. Such fibril tufts entanglethemselves in the fibers of paper and non-woven webs and therebyinterfere with web release and transfer. It has been unexpectedlydiscovered, however, that the presently disclosed abrasion pre-treatmentusing an abrading medium having an effective abrasive grain size of lessthan about 300 mesh, ie, an abrading medium the use of which results ina surface smoothness at least equivalent to that obtained with sandpaperloaded with grit number aluminum oxide abrasive grains as defined by theAbrasive Grain Association and Grinding Wheel Manufacturing Association,will pre-prepare monofilament polymeric fabrics in such a way that theaforesaid wear fibrils are substantially prevented from developing.Accordingly, fiber bond disruption during transfer of a moist paper webcarried and/ or formed and carried thereon is greatly reduced, andincreased intimate drying contact results when pre-prepared monofilamentpolymeric fabric is used to press a moist web onto a drying surface. Itis, accordingly, the principal object of this invention to improve theforegoing features and to overcome other associated problems anddisadvantages.

Another object of this invention is to provide a monofilament polymericfabric for use in papermaking and non- Woven web manufacturingoperations, which fabric has a total knuckle imprint area of about 20%to about 50% of its area and which knuckle imprint area has a surfacefinish at least equal in smoothness to the surface finish induced byabrasion with an abrasive medium having an effective abrasive grain sizeof less than about 300 mesh.

It is another object of this invention to provide a process for theimprovement of monofilament polymeric fabrics for use in papermaking andnon-woven web manufacturing operations wherein such fabrics are abradedprior to such use with an abrasive medium having an effective abrasivegrain size smaller than about 300 mesh, whereby a smooth knuckle imprintarea which will persist during said fabrics life in a papermakingmachine and which is conducive to moist web transfer is produced.

It is yet another object of this invention to provide a monofilamentpolymeric fabric for use in the press and drying sections of apapermaking machine, which fabric presents an increased knuckle imprintarea for use in pressing a moist paper web onto the surface of a Yankeedryer while it contributes materially to the final tensile strength ofthe dried paper product by avoiding the rupture of fiber bonds.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of thisinvention will become apparent as the description thereof proceeds inaccordance with, and as illustrated by, the drawings wherein amonofilament polymeric fabric accorded the treatment of this inventionis illustrated together with a conventional and untreated monofilamentpolymeric fabric for comparison. A graph illustrating the improvement inone measurable indicator of fiber bond rupture improvement gained bysuch treatment is also illustrated. In the drawings the direction ofworn travel is left to right; the fibrillated side of the worn fabric isthe fabric side in moist web contact while the opposite side runsagainst pulleys and suction boxes and like numbers refer to likemonofilament polymeric fabric features.

FIG. 1 is a plan view of an enlarged portion of a conventionalmonofilament polymeric fabric. The monofilament polymeric fabricillustrated has not been accorded the abrasive treatment of the presentinvention and has not been run as an endless or continuous fabric beltin papermaking or non-woven web manufacturing operations.

FIG. 2 is an enlarged cross-sectional view of the monofilament polymericfabric illustrated in FIG. 1, which cross-sectional view furtherillustrates the smooth knuckle surfaces of the warp and woof filamentsand is taken in the cross-machine direction along the line 22 in FIG. 1.

FIG. 3 is an enlarged plan view of a monofilament polymeric fabric whichhas been accorded the abrading pre-treatment of this invention, but hasnot been run on a papermaking machine.

FIG. 4 is an enlarged cross-sectional view of the monofilament polymericfabric illustrated in FIG. 3, which crosssectional view illustrates theincreased knuckle imprint area of sum of the knuckle surfaces developedby 4 the present abrasive pre-treatment and is taken along the line 44in FIG. 3.

FIG. 5 is an enlarged plan view of a monofilament polymeric fabric likethat illustrated in FIG. 3 after a service life of about 400 hours as acontinuous moist web carrier belt in the press section of a papermakingmachine.

FIG. 6 is an enlarged cross-sectional view of the fabric illustrated inFIG. 5, which cross-sectional view illustrates the unusual lack of weardiscovered in the present pretreated monofilament polymeric fabrics andis taken along the line 66 of FIG. 5.

FIG. 7 is an enlarged plan view of a monofilament polymeric fabric likethat illustrated in FIG. 1, i.e., given no abrasive pre-treatment, aftera service life of about 300 hours as continuous moist web carrier beltin the press section of a papermaking machine.

FIG. 8 is an enlarged cross-sectional view of the fabric illustrated inFIG. 7, which cross-sectional view illustrates very well the surfaceroughness, fibrillation and other indications of incipient filamentbreakage and poor moist web transferability which were developed in anuntreated monofilament polymeric fabric under comparable conditions ofservice at only three-quarters of the service life obtained by thefabric illustrated in FIGS. 5 and 6. The cross-sectional view of FIG. 8is taken along the line 88 in FIG. 7.

FIG. 9 is a graph illustrating the improvement in force necessary totransfer a moist paper web from a monofilament polymeric fabric beforeand after pre-treatment according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In describing the preferredembodiment of the invention illustrated in FIGS. 3, 4, 5 and 6 of thedrawings, specific terminology will be adhered to for the sake ofclarity in referring to the features of the monofilament polymericfabrics for use in papermaking and non-Woven web manufacturing of thisinvention. Transfer refers to parting a moist web from a monofilamentpolymeric fabric for deposit on another fabric or surface.

FIGS. 1 and 7 and 2. and 8 are, respectivey, enlarged plan and enlargedcross-sectional views of comparative monofilament polymeric fabricswhich have not received the abrasive pretreatment of the presentinvention. FIGS. 1 and 7 are enlarged plan views of the comparativemonofilament polymeric fabrics which illustrate the before and afterappearance of such fabrics in continuous moist web carrier belt use.FIGS. 2 and 8 are enlarged cross-sectional views which furtherillustrate the before and after appearance of untreated monofilamentpolymeric fabrics.

Referring now to FIGS. 3, 4, 5 and 6 of the drawings, FIGS. 3 and 4illustrate a monofilament polymeric fabric treated according to thepresent invention but not worn, and FIGS. 5 and 6 are enlarged plan andcross-sectional views of the same fabric after about 400 hours ofpapermaking machine wear as a continuous moist web carrier belt. FIGS. 5and 6 illustrate the greatly reduced wear on the fabric attributable tothe pre-treatment of this invention. In particular, comparison betweenFIGS. 3 and 4 and 5 and 6 show that fabrics accorded the treatment ofthis invention prior to use as a continuous moist web carrier belt in apapermaking machine show very little wear of knuckle surfaces 1 after400 hours of papermaking machine use.

This is surprising since it would appear that wear by deliberateabrasion prior to service would decrease service life. As shown in FIGS.5 and 6, however, the knuckle surfaces 1 of the treated monofilamentpolymeric fabric, enlarged as they are in FIGS. 5 and 6, show thedevelopment of very little fibrillation 4, striation 5, fibril tufts 7,fibril masses 8 or other characteristics which result in poor moist webtransferability, fiber bond rupture and decreased drying efiiciency intransfer to a Yankee drying drum or other drying surface.

For comparison, FIGS. 1 and 2 show a monofilament polymeric fabric as itissues from the weaving process; this fabric has not been accorded theabrasive pre-treatment of this invention and has seen no service life.It is apparent from the enlarged plan and cross-section views, shown inFIGS. 1 and 2 respectively, that both the warp filaments 2 and the wooffilaments 3 of this fabric are smooth surfaced and in their enlargedview appear almost as woven glass rods. FIGS. 1 and 2 are included inthe drawings to illustrate the appearance of an unworn monofilamentpolymeric fabric with no pretreatment for contrast with the worn fabricillustrated in FIGS. 7 and 8 of the drawings. FIGS. 1 and 2 also can becompared with FIGS. 3 and 4 to show the physical effect of the presentabrasive pre-treatment in flattening and enlarging the knuckle surfaces1 of the fabrics.

FIGS. 7 and 8 of the drawings illustrate enlarged plan andcross-sectional views of a monofilament polymeric fabric, which viewsare comparable, respectively, with FIGS. 1 and '2, FIGS. 3 and 4 andFIGS. 5 and 6. In FIGS. 7 and 8, however, the fabric shown in FIGS. 1and 2. is illustrated after about 300 hours of service as a continuousmoist web carrier belt on a papermaking machine. Note that theindividual warp filaments 2 and woof filaments 3 of the wornmonofilament polymeric fabric illustrated in FIGS. 7 and 8 havedeveloped striations 5, and that these striations 5 further develop torupture and appear as fibril tufts 7. The striations 5 appear to ruptureat the shoulder of the filament knuckles 6 to form fibril tufts 7 orturned back fibril masses 8. Either the fibril tufts 7 or the turnedback fibril masses 8 are detrimental to the release of a moist paperweb. Furthermore, fibril tufts 7 do not present a flat pressing surfaceconducive to the development of contact for drying on a Yankee surface.In some instances it can be seen in FIGS. 7 and 8 that the filamentbreakdown at the knuckle surfaces 1 is so pronounced that some of thefibril tufts 7 have torn back to the adjacent woof filaments 3, and thewoof filaments 3 are seen to be preventing them from further tearing. Inother instances, where there has been an initial breakdown in the warpfilaments 2 to form striations 5 which parted to form fibril tufts 7,the initial rupture point is seen to be the site of yet anotherincipient filament breakdown. It is assumable that successive filamentbreakdowns of this type would eventually cause rupture of a warpfilament 2 or a woof filament 3.

The graph shown in FIG. 9 illustrates one measure of the moist webfabric transfer characteristics engendered by the pre-treatment of amonofilament polymeric fabric according to the process of the presentinvention. The graph shown in FIG. 9 has as its ordinate the peel forcein grams per inch of web width necessary to part a moist paper web froma monofilament polymeric fabric. The abscissa of the graph has as itsunits the fiber consistency at which the peeling was conducted. Amonofilament polymeric fabric pre-treated according to the process ofthe present invention is seen to require a lower peel force at any fiberconsistency, as a measure of moisture content, than does an untreatedmonofilament polymeric fabric. Although the peel force reduction broughtabout by pretreatment is shown by the graph of FIG. 9 to be only about12% to about 27% of the peel force necessary, the effect of this peelforce reduction in the tensile strength of a moist web is relativelylarge; this is because the peel force is applied to a moist andrelatively weak web, and slight reductions in peel force producerelatively large gains in ultimate tensile strength. Increases in paperweb tensile strength of about 40% to about 90% have been realized fromthe present monofilament polymeric fabric pre-treatment. In requiring alesser peel force to separate a moist web and carrier fabric, thetreated fabric has a lesser tendency to disrupt fiber bonds whentransfers are made in papermaking and non-Woven web manufacturingoperations.

In obtaining the results shown in the graph of FIG. 9, the peel forcewas taken as the average instantaneous pull necessary to peel back aone-inch wide strip of moist web at various fiber consistencies in areversal from its position on a monofilament polymeric fabric. Thenumerical results from which FIG. 9 was plotted were obtained by usingan Instron tester (Model TM, Serial No. 261) to apply the peel force.

FIGS. 3 and 4 of the drawings illustrate the about 20% to about 50%knuckle surface area developed in monofilament polymeric fabrics by thepresent treatment. FIGS. 5 and 6 show that this increased knucklesurface area persists after service as a continuous moist web carrier.The greater knuckle surface area serves to increase contact betweenmoist webs and drying surfaces for more efficient drying.

Applicants point out that the initial abrading treatment given themonofilament polymeric fabric prior to use, as illustrated in FIGS. 3and 4, might be expected to shorten fabric life. The presentpro-treatment, however, not only results in a monofilament polymericfabric life as long if not longer than untreated monofilament polymericfabrics, but also results in the aforementioned advantage of dryersurface contact and avoidance of fiber bond disruption. Comparisonbetween FIGS. 5, 6, 7 and 8 shows that a pre-treated monofilamentpolymeric fabric with a service life of about 400 hours as a continuousmoist web carrier belt is clearly superior in surface condition to a 300hour untreated monofilament polymeric fabric illustrated in FIGS. 7 and8.

As stated above, the pre-treatment of the present invention consists ofabrading the knuckle surfaces of an original monofilament polymericfabric, as illustrated in FIGS. 1 and 2, with a suitable abrasive mediawherein the abrasive grains have a smaller or finer effective abrasivegrain size than about 300 mesh. Applicants have found that the presentpro-treatment performed with an abrasive medium having an effectiveabrasive grain size larger than about 300 mesh will engender an ultimatefabric condition much like that illustrated in FIGS. 7 and 8. When thepre-treatment is carried out with an abrasive medium having an effectiveabrasive grain size of about 300 mesh to about 600 mesh, the ultimatemonofilament polymeric fabric appearance after lengthy periods ofservice as a continuous moist web carrier belt will be found toapproximate the fabric appearance illustrated in FIGS. 5 and 6. A totalknuckle imprint area of about 20% to about 50%, preferably about 30%, ofthe monofilament polymeric fabric area is developed on the pre-treatedfabrics.

Applicants prefer to carry out the present treatment by abrading thesurface of the original monofilament polymeric fabric using a wetsandpaper having an effective abrasive grain size of about 300 mesh toabout 500 mesh as an abrasive medium. Dry sandpapers can also be used,and the abrasive media can be mounted on drums for rotative applicationto fabric knuckle surfaces. The abrading can be performed whilecontinuously showering the fabric with water or other cleansing andlubricating fluid, for example light oil, to remove abraded particlesand facilitate the polishing operation.

Applicants find it necessary to form a smooth and polished surface onthe knuckle imprint area of the monofilament polymeric fabric. To thisend, the present abrading operation can be conducted in several stages.For example, the initial abrasion can be carried out with with anabrasive medium having an effective abrasive grain size of about 300mesh, and this initial abrading operation can be followed by an abrasivepolishing treatment using a water lubricated wet sandpaper having aneffective abrasive grain size of about 500 mesh. Polishing abrasivessuch as talc, rouge and crocus cloth can be used to further polish theknuckle surfaces formed on the monofilament polymeric fabric. Whileapplicants have specified wet and dry sandpapers having an effectiveabrasive grain size of about 300 mesh to about 600 mesh as abrasivemedia for use in carrying out the present pretreatment, other abrasivemeans, for example pierced metal and grinding wheel abrasive mediahaving an equivalent abrasive action can be used to develop the type ofknuckle surfaces 1 shown in FIGS. 3 and 4.

It is to be understood, therefore, that the form of the invention hereinillustrated and described is to be taken as a preferred embodiment.Various changes may be made in the abrading process without departurefrom the invention, and various abrasive media and means of using sameto achieve a pre-treatment for monofilament polymeric fabric asdisclosed herein can be utilized without departing from the spirit orscope of the invention as defined in the attached claims.

The method of monofilament polymeric fabric pretreatment and theresultant monofilament polymeric fabric with increased knuckle imprintarea of this invention has been found to be advantageous in that theabrasion pre-treatment practically eliminates further meaningfulfibrillation wear during the life of a so-treated monofilament polymericfabric as a continuous moist web carrier belt. The additional knuckleimprint area engendered on the pre-treated fabrics is also advantageousin that better contact on a Yankee dryer or other drying surface resultswhen the pre-treated fabric is used to effeet a pressing transfer; thebetter contact is found to increase drying capacity. This latteradvantage is in part due to the knuckle surface height evennessengendered by abrasion.

Since the pre-treated monofilament polymeric fabrics have improvedtransfer characteristics, which improved transfer characteristics resultin higher product tensile strength, use of the pretreated fabrics allowshigher machine speeds during startup and decreases the likelihood of webbreakage and resultant machine down-time. Further improvement intransfer capability can be obtained by coating the pre-treated fabricsWith resin and other release agents.

The enhanced web transfer engendered by abrasive fabric pre-treatmentalso leads to less fiber residue remaining on the treated fabric afterweb transfer. The reduced fiber residue results in a fabric whichremains clean and retains the improved transfer capability. Resultantpaper and non-woven web products are more uniform as regards webcharacteristics such as surface pattern, creping and other physicalcharacteristics. As another important feature of the pre-treatmentdisclosed herein, the monofilament polymeric fabrics of this invention,as a result of their substantially unchanging surface condition, tend toexhibit substantially the same operating conditions and producesubstantially the same products from the time of their first use untilthe time of their replacement.

Having thus defined and described the invention, what is claimed is:

1. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-woven webmanufacturing operations, whereby the parting characteristics of saidfabric for moist papers and non-woven webs supported thereon aresubstantially improved, which process comprises the steps of:

(1) increasing the knuckle imprint area of said fabric on the websupporting surfaces of said fabric by abrading away the knuckle surfacesthereof with at least one abrasive medium having an effective abrasivegrain size of about 300 mesh to about 600 mesh, and

(2) supporting said papers and non-woven webs by said fabric on itsabraded surface.

2. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-woven webmanufacturing operations as claimed in claim 1 wherein the abrasivemedium is wet sandpaper and the knuckle surfaces are lubricated withwater while increasing the knuckle imprint area.

3. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-Woven Webmanufacturing operations as claimed in claim 1 wherein the abrasivemedium is drum mounted dry sandpaper having an effective abrasive grainsize of about 300 mesh.

4. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-woven webmanufacturing operations as claim in claim 1 wherein the abrasive mediumis first wet sandpaper having an effective abrasive grain size of about300 mesh and second Wet sandpaper having an effective abrasive grainsize of about 500 mesh.

5. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-woven webmanufacturing operations as claim in claim 1 wherein the abrasive mediumis Wet sandpaper having an effective abrasive grain size of about 300mesh and the abraded knuckle surfaces are thereafter polished withcrocus cloth.

6. A process for pre-treating a monofilament polymeric fabric for use asa formation and carrier fabric in papermaking and non-woven webmanufacturing operations as claimed in claim 1 wherein the abrasivemedia is first wet sandpaper having an effective abrasive grain size ofabout 300 mesh and second wet sandpaper having an effective abrasivegrain size of about 500 mesh and the abraded knuckle surfaces arethereafter polished with rouge.

7. The combination of a monofilament polymeric fabric for use as aformation and carrier fabric in paper making and non-woven webmanufacturing operations with a Web supported by said fabrics, whichmonofilament polymeric fabric has a knuckle imprint area, supportingsaid web, of about 20% to about 50% of the surface area of said fabric,and the knuckle surfaces comprising said knuckle imprint area havesurface finishes which are at least equal in smoothness to the surfacefinish induced by abrasion with an abrasive medium having an effectiveabrasive grain size of about 300 to about 600 mesh, said web beingsupported by the abraded knuckle surfaces of said fabric.

8. A monofilament polymeric fabric for use as a formation and carrierfabric in papermaking and nonwoven web manufacturing operations asclaimed in claim 7 wherein monofilament polymeric fabric has a knuckleimprint area equal to about 30% of the surface area of said fabric.

References Cited UNITED STATES PATENTS 2,435,467 2/ 1948 Spencer 162-FFMFOREIGN PATENTS 1,009,890 11/1965 Great Britain 162FFM 676,070 2/1930France l39425.5

1,357,305 2/1964 France 139---425.5

, 0 REUBEN FRIEDMAN, Primary Examiner T. A. GRANGER, Assistant ExaminerUS. Cl. X.R.

